RITA Ion Thruster

Ion Propulsion
How it Works
Advantages
Applications
Heritage
Thruster RIT-10
Thruster RIT-XT
Thruster RIT-22
Xenon Regulator
Eureca
Artemis

Advantages of Astrium Radio Frequency Ion Propulsion.

An insight into performance, heritage and world record breaking achievement.

Compared to Ion propulsion, chemical propulsion provides short bursts of high thrust necessary to accomplish Earth to orbit and space missions demanding high accelerations. Ion propulsion, on the other hand, provides quite a low thrust over a long period and can achieve more than 10 times higher exhaust velocity, thereby enabling a far higher final velocity than chemical propulsion.

The mark of excellence, that distinguishes ion propulsion from chemical propulsion, is propellant consumption. Chemical propulsion, provides exhaust velocities of around 3 to 5 km/second, whereas ion propulsion can achieve exhaust velocities above 30 km/second. This advantage may be traded for 6 to 20 times more velocity increment per kg of propellant, or alternatively, an equivalent increase in mission life, or a reduction in propellant mass and volume enabling either an increase in payload or reduction in specific launch cost.

Amongst the various electric propulsion technologies, ion propulsion is shown to have the highest specific impulse amongst the available alternatives.

For a variety of future space applications, ion propulsion provides the economic means and performance access that cannot be achieved with chemical propulsion alone.

Astrium Radio Frequency Ion Propulsion
Astrium Lampoldshausen have concentrated their ion propulsion development on radio frequency ion propulsion, a German technology that started development in the 1960's.

The Astrium Radio Frequency Ion Thruster Assembly (RITA) is a complete ion propulsion system with a 45 year history of heritage and achievement. The RITA system has already set a number of world performance and endurance records both in space and on ground.

The RITA ion propulsion system is space-flight proven and qualified and provides substantial cost savings / payload gains and many more advantages. RITA is propulsion for the future with ample margins for evolutionary performance growth.

Currently, the latest RITA ion propulsion system, the RITA-22, can achieve exhaust velocities in excess of 40 km/second, yielding a nominal specific impulse up to 6200 seconds - a performance 30 - 50% higher than alternative ion propulsion systems.

Advantages of Astrium Radio-frequency Ion Propulsion

1) Very high specific impulse
RIT provides a specific impulse ranging from 3,000 to over 6,000 seconds. For each kg of propellant, the RIT thruster will operate 10 to 20 times longer than a chemical thruster of equivalent thrust. Thereby, the advantages of RIT propulsion includes:

• Ideally suitable for long duration deep space and interplanetary missions.
• Significant life increase for GEO satellites and / or:
• Significant payload increase, and / or:
• Significant cost saving.
  

2) 750 kg more payload for a GEO satellite
For a typical 4 tonne GEO satellite, the use of an RIT propulsion system enables a propellant saving of around 750 kg - which may be used for an additional equivalent payload mass. (See cost / mass savings graph).

3) 15 Mio Euro cost saving for a GEO satellite
The mass gain available to a typical 4 tonne GEO satellite may be traded for a substantial cost saving. Assuming a specific cost of €20,000 to transfer 1 kg into GTO, the 750 kg mass saving provided by RIT propulsion translates to a €15 Mio cost saving (see cost / mass savings graph).

4) Substantial increase in mission duration
Compared to chemical propulsion systems of equivalent thrust, the RIT propulsion system provides a number of distinct advantages that supports long duration missions, including:

• 10 to 20 times longer operation per kg of propellant.
• Unlike chemical propulsion, RIT propulsion is inherently simpler, uses a benign monopropellant and does not endure the life constraining limitations and reliability issues associated with combustion.
• Qualified operational life of RIT far greater than chemical thrusters.

5) High reliability and confidence
Initial research and development into RIT propulsion in Europe commenced in the mid 1960's at the University of Giessen, Germany. This pioneering work was later reinforced together with, and under the leadership of Astrium in 1970, supported by their industrial specialist team including Alcatel, Polyflex, Laben Proel and Astrium. Today, Astrium Radio-frequency Ion propulsion has repeatedly demonstrated high reliability and predictability attributed to:

• Huge development and qualification heritage from plasma propulsion.
• Evolution and refinement from development and previous space qualified ion thrusters
• Over 65,000 hours of operational experience in space.
• Over 50,000 hours successful testing.
• Extensive testing, deliberate failure mode causation, rectification and avoidance.
• Fully developed and qualified hardware.
• Flawless and predictable operation in space.
• Thousands of predictable, reproducible restarts demonstrated on ground and in space.
• Simple and benign operating behaviour of the Astrium Radio-frequency Ion Thruster Assembly.
• Use of benign monopropellant Xenon.
• Establishment of accurate modelling, analytical and predictive tools.
  

6) Environment and payload friendly
Astrium Radio-frequency Ion propulsion uses Xenon as propellant. Xenon is a non toxic, odourless, colourless inert gas and entirely harmless unless present in sufficient quantity to exclude oxygen from the lungs. Unlike chemical thruster propellants, the advantages of Xenon include.

• No products of combustion to contaminate the space environment or degrade sensitive payload instruments, optics etc.
• No fire, germ cell or hypergolic explosion risk.
• Least risk in the event of leakage during ground operations.
• Non-combustible.
• Safe to handle, non-toxic, non-carcinogenic.
• Easier handling and containment.
• Simpler and lower cost MGSE.

7) Planetary Access
RIT enables science and interplanetary missions that cannot be economically realised with chemical propulsion due to:

• Significantly longer operational life.
• More tolerant to long duration dormant and coast phases.
• Significantly greater number of restarts.
• Significantly reduced propellant mass for total mission impulse.
• No propellant conditioning issues customarily associated with chemical thrusters.
• Higher safety due to the use of an inert, non-explosive propellant.
• Reduced propulsion system mass and volume.
• High reliability, low risk and economic feasibility.

8) Performance Growth
Within the current state of art, ion propulsion offers more potential for future performance growth than alternative electric propulsion technologies.

9) Heritage
Almost 45 years of research, development and refinement into Radio Frequency Ion propulsion.

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